First off the car, 1992 Canaro RS 5.0 T5 manual TBI. I purchased this car not long ago, it ran great st first but then got more and more weird. Well while trying to dig out the gremlins, I found through the help of some folks here, it had the ECM from a late 80s S10 with a V6. So i found a replacement of the right kind and hooked it up. From the get go it is hard to start, and after a couple minutes of chugging it will finally idle pretty smoothly around 1000 rpms. Also with the "New" computer its throwing a code 42 and 44. I looked the codes up and 42 is a bad O2 sensor. Upon purchasing the car I did a full tune up and I put a new one on there. Not that it couldnt have gone bad of course. Just putting that out there. I also did some datalogging since I'm stumped. With both computers, especially the S10 computer, the O2 sensor values fluctuated alot. I'm not sure though if it's with range or not. So here's what I've got. Any guru's have any guidance for me? Also I attached datalogs from both ECMs the S10 computer 8062 and the proper ECM 8746.s

 

Do you have the correct PROM in the new ECM?

 

In theory yes. It has the prom that came in it. I purchased it from a used parts seller, for what that is worth and it had a prom installed. It was listed as a used ECM from a 92 RS. And the part number is correct. Of course I assume the ECM and PROM are both correct and working properly in this situation.